Argostemma cordatum (Rubiaceae), a new species from Vietnam

Abstract

Argostemma cordatum, a new species of Rubiaceae, is described and illustrated. The species was discovered in 2014 during a botanical survey of the Chu Yang Sin National Park (Dak Lak province, Southern Vietnam). Argostemma cordatum possesses a solitary large leaf per plant (along with one very small leaf). The new species differs from morphologically similar species mainly by the small size of the enlarged leaf and cordate base of the enlarged leaf. It is also characterized by the following features: plant completely glabrous, stipules minute and reduced to papillate warts, inflorescence with all axes elongated, anthers coherent into anther cone and dehiscent by longitudinal slits, style slightly exserted. An extended description of the vegetation in the area inhabited by A. cordatum is provided.

Notes on taxonomy of the genus Argostemma (Rubiaceae) from Vietnam

“…Detailed examination of the specimens and studies on the protologues and type specimens of previously known species revealed that the morphological characters of these specimens match with those of Argostemma pictum Wall. -a species distributed mainly in Myanmar, Thailand, Peninsular Malaysia, and Laos (Sridith, 2007;Lanorsavanh & Chantaranothai, 2019), however, this species has not yet been reported for Vietnam in previous treatments (Pitard, 1923;Pham, 2003;Choudhary et al, 2013;Govaerts et al, 2017;Nuraliev et al, 2017;Quang et al, 2019;Do et al, 2020). Therefore, we report here A. pictum as a new record for the flora of Vietnam bringing the number of species in the genus to 10, of which, six species, i.e.…”

“…Although several taxonomic treatments of the genus were published for geographical areas, e.g. the Malay peninsula and peninsular Thailand (Ridley, 1923;Sridith, 1999Sridith, , 2007Sridith & Puff, 2000), Laos (Lanorsavanh & Chantaranothai, 2013, 2019, China (Chen et al, 2011), and Vietnam (Pitard, 1923;Pham, 2003), a worldwide monographic study has not yet been attempted. The Malay Peninsula, Peninsular Thailand and Borneo were considered as centres of diversity of Argostemma; 31 species were recorded for the flora of Thailand (Sridith, 2007).…”

Typification and novelties in Rubiaceae for the flora of Vietnam

“…86 genera and 510 species (Pitard, 1922;Ho, 2003;Tran, 2005). Of late, several new species belonging to Rubiaceae have been described from Vietnam including four species of Argostemma (Choudhary et al, 2013;Nuraliev et al, 2017;Bui et al, 2019;, two species of Leptomischus (Wu et al, 2020;Tran et al, 2021a), 15 new species of genus Lasianthus (Dang et al, 2022) along with several new records. The Rubiaceae are highly diverse in Indo-China, however, the taxonomic inventories of Rubiaceae in the regional flora remain incomplete.…”

Argostemma quarantena (Rubiaceae, Ruboideae), a new species from southern Western Ghats, India

“…A dozen of new species have been added to the genus from S.E. Asia over the last 10 years (Sridith 2012;Choudhary et al 2013;Lanorsavanh and Chantaranothai 2016;Nuraliev et al 2017;Quang et al 2019;Hsu et al 2020;Lanorsavanh et al 2020;Van Do et al 2020).…”